1. Field of the Invention
The present invention relates to an apparatus for recording and reproducing data with respect to an optical disk, and more particularly, to an optical disk recording/reproducing apparatus that is capable of determining a reproducing speed according to a bit rate of an optical disk, and to reproduce data from the optical disk at an optimal speed. Also, the present invention relates to a method of determining an optimal reproducing speed of the optical disk recording/reproducing apparatus.
2. Description of the Related Art
A digital video disk player (DVDP) or digital video express player (Divx) is a kind of an optical disk recording/reproducing apparatus for recording or reproducing data on or from an optical disk, such as a digital video disk (DVD), so as to provide an image of high quality. The optical disk recording/reproducing apparatus comprises a spindle motor for rotating the optical disk at a certain speed and a laser diode provided to an optical pickup for recording or reproducing information on or from the optical disk.
The optical disk recording/reproducing apparatus generally includes a function of adjusting a rotational speed of the optical disk by controlling the spindle motor so as to regulate the reproducing speed of the optical disk. In the optical disk recording/reproducing apparatus, the reproducing speed of the optical disk is generally referred to as multiple speed depending upon the rotational speed of the optical disk rotated by the spindle motor. In the case of operating the optical disk recording/reproducing apparatus at high multiple speed, a rotational speed of the spindle motor is rapidly increased than the case of operating the apparatus at low multiple speed, so that the optical pickup reads the data from the optical disk at the high multiple speed per unit time.
The reproducing speed of the optical disk recording/reproducing apparatus, such as Divx player, is determined at constant low or high multiple speed depending on the selection of a user. Accordingly, the reproducing speed of the optical disk is uniformly selected for all bit rates, regardless of a bit rate indicative of a density of a digital signal stored in the optical disk. Even though an optical disk of a different bit rate is loaded into the optical disk recording/reproducing apparatus, the data can be reproduced at a constant selected multiple speed.
In the case where a bit rate of the optical disk is high, however, an amount of data to be read per unit time is increased. At that time, if the optical disk recording/reproducing apparatus is operated at a low multiple speed to reproduce the optical disk, a digital signal of high bit rate is not read at a certain speed sufficient for reproducing the optical disk. For moving pictures, therefore, there is a problem in that a performance of the optical disk recording/reproducing apparatus of reproducing a digital signal from the optical disk is deteriorated, so that a picture or sound which should be continuously reproduced is interrupted.